It is proven that infection with Human papillomavirus (HPV) can increase the risk for vaginal cancer. The human papillomavirus (HPV) is a group of sexually transmitted viruses. The risk for getting infected with these viruses can be controlled and reduced by conducting several types of responsible sexual behaviors:

Delay sexual intercourse and an active sexual life, especially if you are an young girl. HPV is more common among young women than in women over the age of 30.
Limit the number of sexual partners.
Avoid sexual contact with partners that are themselves engaged in sexual activities with multiple partners.
Do not trust condoms to protect you from HPV. Recent studies have proven that condoms do not protect against HPV infection, because the virus can be contacted through a skin-to-skin contact with an HPV infected area (such as the skin of the genitals or anal area).
However, there are type of vaginal cancer which are not related to the HPV infection, so this approach won’t entirely protect a women from not developing vaginal cancer, although it does help.

Another risk factor, that can be easily controlled and avoided, is smoking. Unfortunately, cigarette smoking has been proven to increase the risk for vaginal cancer. The two main approaches that can help are: do not start smoking if you are a nonsmoker or quit smoking if you are an active smoker.